JP2017141336A - Inkjet oily recording liquid and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet oily recording liquid that secures discharge stability as well as the color development and fastness of an image obtained therefrom by stably dispersing a pigment in a recording liquid, and an inkjet recording method.SOLUTION: An oily inkjet recording liquid has a pigment, an oily medium, and a resin. For the pigment, a 10% integrated value (D10) of number distribution in primary particle diameter is 40 nm or more and 80 nm or less and a 90% integrated value (D90) is 90 nm or more and 150 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to an oil-based recording liquid for inkjet and an inkjet recording method.

  Development of office-use inkjet printers is ongoing. An office use printer is required to be capable of high-speed printing at high image quality on a recording medium such as plain paper, and to be able to handle a finisher such as bookbinding after printing. For this reason, as a characteristic required for the recording liquid used in this printer, it is possible to secure a high print density at a high speed for plain paper, and to prevent back-through to enable double-sided printing, Furthermore, it is required that paper deformation such as cockling and curling does not occur after high-speed printing. When an aqueous recording liquid containing an aqueous medium is used as the ink, paper deformation such as cockling and curling may occur after high-speed printing on plain paper. Oil-based recording liquids are also being developed.

  In oil-based recording liquids, dyes or pigments are used as coloring materials, but pigments are preferred because of their good light resistance and water resistance. In many cases, the dye is dissolved in the solvent of the oil-based recording liquid, whereas the pigment is dispersed in the solvent of the oil-based recording liquid, so that the dispersion stability in the recording liquid is ensured. In addition, it is necessary to use in combination with a pigment dispersant or to use a self-dispersing pigment. Therefore, there is a technique for improving the printing density at the time of printing at a low resolution and further improving the ejection property from the nozzle by defining the dispersed particle diameter and content of the pigment within a predetermined range (for example, patents). Reference 1).

JP 2010-209188 A

  However, in the above technique, the dispersed particle diameter of the pigment is specified, but no mention is made of the primary particle diameter of the pigment. The dispersed particle size of the pigment and the primary particle size do not necessarily correlate. When the primary particle size of the pigment is too small, the pigment is not stably dispersed in the recording liquid, and the light resistance is poor. In some cases, the fastness of the ink may decrease, and the ejection stability and color developability may also decrease. These problems are difficult to solve with the above technique.

  Accordingly, some aspects of the present invention solve at least a part of the above-described problems, thereby stably dispersing the pigment in the recording liquid, thereby improving the ejection stability, the color developability of the obtained image, and the fastness. Another object of the present invention is to provide an ink jet recording liquid and an ink jet recording method in which properties are ensured.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the oil-based recording liquid for inkjet according to the present invention is:
Containing a pigment, an oily medium, and a resin;
10% integrated value (D10) of the number distribution of the primary particle diameter of the pigment is 40 nm or more and 80 nm or less, and 90% integrated value (D90) is 90 nm or more and 150 nm or less.

  According to the recording liquid according to the application example, since the number distribution D10 and D90 of the primary particle diameter of the pigment is in the above range, the pigment is stably dispersed in the recording liquid, and the ejection stability and the obtained image are obtained. It is possible to provide an oil-based recording liquid for ink jet in which color development and fastness are ensured.

[Application Example 2]
In the above application example,
The resin may be at least one selected from the group consisting of a urethane-modified acrylic resin, a fatty acid-modified alkyd resin, and a urethane-modified alkyd resin.

[Application Example 3]
In the above application example,
The oily medium contains a petroleum solvent, a fatty acid ester and a higher alcohol;
The petroleum solvent may be a naphthenic solvent.

[Application Example 4]
In the above application example,
The content of the resin dissolved in the oily medium is 0.1% by mass or more and 2% by mass or less.

[Application Example 5]
In the above application example,
The mass ratio of the pigment and the dispersant (pigment / dispersant) in the oil-based recording liquid for inkjet may be in the range of 0.5 or more and 2.0 or less.

[Application Example 6]
One aspect of the inkjet recording method according to the present invention is:
Recording is performed using the oil-based recording liquid for inkjet described in any one of Application Examples 1 to 5.

1 is a diagram schematically illustrating an example of an ink jet recording apparatus that performs an ink jet recording method according to an embodiment. FIG.

  Hereinafter, preferred embodiments of the present invention will be described. The embodiment described below describes an example of the present invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention.

1. Ink-jet oil-based recording liquid The ink-jet oil-based recording liquid according to this embodiment (hereinafter also simply referred to as “oil-based recording liquid” or “ink”) contains a pigment, an oil-based medium, and a resin. The 10% integrated value (D10) of the number distribution of primary particle diameters is from 40 nm to 80 nm, and the 90% integrated value (D90) is from 90 nm to 150 nm.

Here, the “oil-based recording liquid” in the present specification is an ink containing an organic solvent as a main component and means an ink that does not substantially contain water. In addition, “substantially free of water” means that water is not intentionally added when the ink is produced, and contains a minute amount of water that is inevitably mixed during the production or storage of the ink. It does not matter.

  The specific water content of the “oil-based recording liquid substantially free of water” is preferably such that the water content in the oil-based recording liquid is 3% by mass or less, more preferably 1% by mass or less. More preferably, it is less than 0.05% by mass, more preferably less than 0.01% by mass, still more preferably less than 0.005% by mass, and most preferably less than 0.001% by mass.

  Hereinafter, components contained in the oil-based recording liquid for inkjet and components that may be contained will be described.

1.1. Colorant The oil-based recording liquid according to this embodiment contains a pigment. As the pigment, a pigment such as a colored inorganic pigment or a colored organic pigment usually used in conventional oil-based inkjet ink compositions can be used. These pigments may be used alone or in combination of two or more.

  The primary particle diameter of the pigment in the oil-based recording liquid is such that the 10% integrated value (D10) of the number distribution of the primary particle diameter of the pigment is 40 nm to 80 nm and the 90% integrated value (D90) is 90 nm to 150 nm. As long as the hue of the pigment is white, black, yellow, magenta, cyan, red, green, blue or orange, conventionally known inorganic pigments and organic pigments can be used without particular limitation.

  Here, in this specification, the primary particle diameter of the pigment is obtained as follows. First, the pigment powder is observed with a TEM (transmission electron microscope) or SEM (scanning electron microscope), and images of individual pigment particles are acquired. Next, the particle diameter (diameter) is measured from the center of gravity of the acquired image of each pigment particle at an interval of 1 ° in an angle range of 0 ° to 179 °, and the average value of the 180 measured particle sizes is the same. The primary particle diameter of pigment particles was used. Further, the 10% integrated value (D10) and 90% integrated value (D90) of the number distribution of the primary particle diameters of the pigments were determined from the measured primary particle diameters of 100 or more pigment particles thus obtained. .

The inventor of the present invention indicates that this recording liquid has a 10% integrated value (D10) of the number distribution of the primary particle diameter of the pigment of 40 nm to 80 nm and a 90% integrated value (D90) of 90 nm to 150 nm. It was found that the color developability of the image obtained by using is improved specifically. This is a phenomenon that has not been seen with aqueous recording liquids. In aqueous recording liquids, it is known that when the pigment particle size is small, the pigment particles penetrate into the paper, so that the color developability generally decreases (for example, DIC TECHNIC REVIEW No. 8/2002).
P. 21 etc.). On the other hand, the detailed mechanism of high color development in an oily medium is unknown, but is roughly estimated as follows.

For example, color pigments are formed from molecular crystals in which aromatic molecules such as phthalocyanine molecules and quinacridone molecules are laminated. These molecules have surface chemical properties derived from electronic states such as polarities within the molecules, and the surface chemical properties also depend on the layered state of the molecules. For example, when the primary particle diameter of the pigment is large, the highly active site in the molecule is relaxed by the intermolecular interaction, and as a result, the pigment surface is covered with the less active site. On the other hand, when the primary particle diameter of the pigment is small, the active site cannot be relaxed and the highly active site is exposed on the pigment surface. This highly active site has an electrical polarity, and the electrostatic interaction causes an interaction between the pigment particles. As a result, when the recording liquid lands on the paper surface, the pigment particles agglomerate there, Deposit on top. When the pigment is unevenly distributed on the paper surface in this way, the color developability as printing is enhanced. It is presumed that the above effect is remarkable in an oily medium because the dielectric constant of the oily medium is lower than that of the aqueous medium.

  In addition, when the molecular crystal of the pigment is small, it is known that the ink jet method is excellent in ejection stability. However, if the molecular crystal of the pigment is too small, the resistance to ultraviolet rays and oxidizing gas is extremely deteriorated. For this reason, in order to achieve both color development and fastness of the image, the 10% integrated value (D10) of the number distribution of the primary particle diameter of the pigment is 40 nm or more and 80 nm or less, and the 90% integrated value (D90) is 90 nm. It is important that the thickness is 150 nm or less, and it has been found that an image using a recording liquid using the same has not only high color developability but also high light resistance and ozone resistance of the image.

  Here, when D10 is less than 40 nm, image fastness may deteriorate. On the other hand, if it exceeds 80 nm, clogging of the nozzle may occur and a recovery failure due to cleaning may occur. On the other hand, when D90 is less than 90 nm, color developability on a permeable recording medium such as plain paper may be deteriorated. If D90 exceeds 90 nm, the sedimentation stability of the recording liquid may not be ensured.

  The dispersed particle diameter often used as the particle diameter of the pigment means the diameter of dispersed particles (composite particles) formed from a pigment and a resin (dispersant) for dispersing the pigment in a medium. The composite particles of the pigment and the resin cannot reflect the size of the pigment because the resin adsorption amount is large, and may not correlate with various characteristics such as image fastness due to the pigment characteristics. Therefore, in the present invention, it is possible to effectively design the performance of the recording liquid including various characteristics due to the pigment by using D10 and D90 of the primary particle diameter of the pigment as parameters and controlling them. It becomes. Further, by controlling the primary particle diameter of the pigment, the recording liquid is excellent in storage stability, ejection stability, and sedimentation.

  Examples of pigments that can be used in the oil-based recording liquid according to this embodiment include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments; phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxanes Polycyclic pigments such as gin pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments; dye lakes such as basic dye-type lakes and acid dye-type lakes; nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments, etc. Organic pigments; inorganic pigments such as carbon black.

  More specifically, examples of the pigment when the oil-based recording liquid according to this embodiment is magenta or red ink include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 170, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 194, C.I. I. Pigment red 209, C.I. I. Pigment red 222, C.I. I. Pigment red 224, C.I. I. Pigment violet 19 and the like.

Examples of the pigment used when the oil-based recording liquid used in the present embodiment is orange or yellow ink include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment orange 64, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment Yellow 1
28, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. And CI Pigment Yellow 180.

  Examples of the pigment when the oil-based recording liquid used in this embodiment is green or cyan ink include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment green 7, C.I. I. And CI Pigment Green 36.

  Examples of the pigment when the oil-based recording liquid used in the present embodiment is black ink include carbon black.

  Examples of the pigment when the oil-based recording liquid used in the present embodiment is white ink include C.I. I. Pigment white 6, C.I. I. Pigment white 18, C.I. I. And CI Pigment White 21.

  As a commercially available product, for example, carbon black MA11, MA100, MA220, MA600a, # 40, and # 44 manufactured by Mitsubishi Chemical Corporation are preferably cited as black pigments. Examples of pigments other than black include SYMULERBrillant Carmine 6B, SYMULER Red, FASTOGEN Super Magenta, SYMULER Fast Yellow, FASTOGEN Blue 4RO-2, FASTOGEN VST, and FASTOGEN VST, manufactured by Dainippon Ink Co., Ltd. These pigments may be used alone or in appropriate combination.

  The pigment content in the oil-based recording liquid used in the present embodiment can be appropriately selected depending on the application and printing characteristics. However, since excellent concealment and color reproducibility can be obtained, the total mass (100 % By mass) is preferably contained in the range of 0.01% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and particularly preferably 1% by mass to 10% by mass. % Or less.

1.2. Oily medium The oily recording liquid according to this embodiment contains an oily medium. Here, the “oil-based medium” in this specification refers to a liquid medium in which a pigment or the like is dispersed contains an organic solvent, and refers to a liquid medium at normal temperature and pressure. Here, when the oil-based medium is an organic solvent-containing material composed of an organic solvent and a mixture other than the organic solvent, the organic solvent content exceeds 5% by mass.

  As the oil-based medium used in the oil-based recording liquid according to the present embodiment, any of various known vegetable oils and / or petroleum-based solvents can be used, and both nonpolar organic solvents and polar organic solvents are used. Is possible.

1.2.1. Non-polar organic solvent Examples of the non-polar organic solvent used in the oil-based recording liquid according to the present embodiment include hydrocarbon solvents such as naphthenic, paraffinic, and isoparaffinic petroleum solvents, fluorine-based solvents, and silicon-based solvents. A solvent etc. are mentioned. As these nonpolar organic solvents, commercially available ones may be used. For example, aliphatic saturated hydrocarbons such as dodecane, Isopar manufactured by ExxonMobil Co., Ltd., Exsol, manufactured by JX Nippon Oil & Energy Corporation AF Solvent, Normal Paraffin H, AS Sol manufactured by Wilvie Co., Ltd., Dust Clean manufactured by Matsumura Oil Co., Ltd., Sansen Co., Ltd. manufactured by Sun Oil Co., Ltd., and Thumper manufactured by AGC Seimi Chemical Co., Ltd.

1.2.2. Polar organic solvent Examples of the polar organic solvent used in the oil-based recording liquid according to this embodiment include ester solvents, alcohol solvents, amide solvents, fatty acid solvents, ether solvents, and the like.

  Examples of the ester solvent include higher fatty acid esters having 5 or more carbon atoms in one molecule, preferably 9 or more carbon atoms in one molecule, more preferably 12 to 32 carbon atoms in one molecule. For example, isodecyl isononanoate, isotridecyl isononanoate, isononyl isononanoate, methyl laurate, isopropyl laurate, isopropyl myristate, isopropyl palmitate, isooctyl palmitate, hexyl palmitate, isostearyl palmitate, isooctyl isopalmitate, olein Methyl acid, ethyl oleate, isopropyl oleate, butyl oleate, hexyl oleate, methyl linoleate, isobutyl linoleate, ethyl linoleate, butyl stearate, hexyl stearate, isotearic acid Octyl, isopropyl isostearate, 2-octyldodecyl pivalate, diisopropyl adipate, diisopropyl sebacate, diethyl sebacate, propylene glycol monocaprylate, trimethylolpropane tri-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate, etc. Can be mentioned. In addition, soybean oil fatty acid methyl, soybean oil fatty acid isobutyl, linseed oil fatty acid methyl, linseed oil fatty acid butyl, linseed oil fatty acid propyl, linseed oil fatty acid 2-ethylhexyl, tung oil fatty acid methyl, tall oil fatty acid which are esters of drying oil fatty acid and alcohol Examples include methyl and tall oil fatty acid isobutyl.

  Examples of the cyclic ester include β-propiolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone.

  Examples of the alcohol solvent include methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, isopropyl alcohol, and fluorinated alcohol. In particular, the alcohol solvent is preferably an aliphatic higher alcohol having 12 or more carbon atoms in one molecule. For example, higher solvents such as hexadecanol, isomyristyl alcohol, isopalmityl alcohol, isostearyl alcohol, oleyl alcohol and the like. Alcohol etc. are mentioned.

  Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, Examples include trimethylolethane and trimethylolpropane.

  Examples of the amide solvent include acetamide, dimethylacetamide, N-methylpyrrolidinone and the like.

  Examples of the fatty acid solvent include fatty acids having 4 or more carbon atoms in one molecule, preferably 9 to 22 carbon atoms in one molecule. For example, isononanoic acid, isomyristic acid, hexadecanoic acid, isopalmitin Acid, oleic acid, isostearic acid and the like can be mentioned.

Examples of the ether solvent include glycol ethers such as diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol dibutyl ether, and acetates of glycol ethers.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, and cyclohexanone.

  Amines may be blended, for example, hydroxylamines such as triethanolamine, tripropanolamine, tributanolamine, N, N-dimethyl-2-aminoethanol, N, N-diethyl-2-aminoethanol, etc. Can be mentioned.

  One or a plurality of oily media exemplified here can be added to the oily recording liquid in an appropriate amount.

  In the present invention, it was confirmed that when an aromatic solvent, particularly a naphthene solvent, is selected as the oily medium, the dispersion stability effect of the pigment is remarkably exhibited. This is presumably because the solvent molecules are similar in polarity and molecular structure to the pigment constituent molecules. For this reason, when a naphthenic solvent is used, an oil-based recording liquid in which ejection stability, color developability of the obtained image, and fastness are ensured can be obtained.

1.3. Resin The oil-based recording liquid according to the present embodiment contains a resin as a dispersant. As the resin, any dispersant used in a normal oil-based recording liquid can be used from the viewpoint of improving the dispersion stability of the pigment. The pigment dispersant that can be used in the present invention is not particularly limited as long as the pigment is stably dispersed in a solvent. For example, Solsperse 5000, Solsperse 13940, Solsperse 11200, Solsperse 21000, manufactured by Nippon Lubrizol Co., Ltd. Solsperse 28000 etc. are mentioned.

  In particular, a resin selected from urethane-modified acrylic resin, fatty acid-modified alkyd resin, and urethane-modified alkyd resin is effective for coating the pigment surface including the highly active site on the pigment surface to ensure dispersion stability. I found out. When the resin is any one of these, the pigment is more stably dispersed in the recording liquid, so that the droplet forming property when ejected from the inkjet nozzle is improved. For this reason, the ejection stability is improved, and continuous stable ejection is possible particularly in high-speed line-type ink jet recording. Further, since the pigment is more stably dispersed in the recording liquid, the color developability and fastness of the obtained image are ensured.

  In the oil-based recording liquid according to the present embodiment, the content of the dispersant can be appropriately selected depending on the pigment to be dispersed, but the content of the resin dissolved in the oil-based medium in the oil-based recording liquid is 0. The content is preferably 1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 5% by mass or less. Here, the “dissolved” resin refers to a resin present in a continuous layer of an oily medium that is not adsorbed on the pigment surface in the recording liquid. In this range, since the pigment is more stably dispersed in the recording liquid, ejection stability, color development of the obtained image, and fastness are ensured. The mass ratio of pigment to dispersant (pigment / dispersant) in the oil-based recording liquid is preferably in the range of 0.5 to 2.0, more preferably 1.0 to 1.5. It is as follows.

1.4. Other Components Other additives contained in a normal oil-based recording liquid may be further added to the oil-based recording liquid according to the present embodiment. Examples of other additives include stabilizers such as antioxidants and ultraviolet absorbers, surfactants, binder resins, and the like.

<Antioxidant>
Examples of the antioxidant include BHA (2,3-butyl-4-oxyanisole), BHT (2,6-di-t-butyl-p-cresol) and the like.

<Ultraviolet absorber>
Examples of the ultraviolet absorber include benzophenone compounds and benzotriazole compounds.

<Binder resin>
In the oil-based recording liquid according to this embodiment, a binder resin may be added for the purpose of fixing the pigment to the recording medium or adjusting the viscosity of the recording liquid. Examples of the binder resin include acrylic resin, styrene acrylic resin, rosin modified resin, phenol resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride vinyl acetate copolymer resin, cellulose acetate butyrate and the like. Resin, vinyltoluene-α-methylstyrene copolymer resin, and the like. These binder resins may be used alone or in combination of two or more. By containing these resins, the fixing property to the recording medium can be improved and the abrasion resistance is also improved.

  The solid content of the binder resin in the oil-based recording liquid according to the present embodiment is preferably 0.05% by mass to 15% by mass, more preferably 0.1% by mass to 10% by mass, and still more preferably 1%. It is from 5% by mass to 5% by mass.

<Surfactant>
The oil-based recording liquid according to the present embodiment is a silicon-based surfactant, a fluorine-based surfactant, or a nonionic surfactant from the viewpoint of reducing surface tension and improving wettability with a recording medium. A polyoxyethylene derivative may be added.

  As the silicon surfactant, it is preferable to use polyester-modified silicon or polyether-modified silicon. Specific examples include BYK-315, 315N, 347, 348, BYK-UV3500, 3510, 3530, 3570 (all manufactured by Big Chemie Japan Co., Ltd.).

  As the fluorosurfactant, it is preferable to use a fluorine-modified polymer. Specific examples include BYK-340 (manufactured by BYK Japan), Surflon S-211, S-131, S-132, S-. 141, S-144, S-145 (manufactured by Asahi Glass Co., Ltd.), aftergent 100, 150, 251 (manufactured by Neos Co., Ltd.), Megafax F477 (manufactured by DIC Corporation), FC-170C, FC-430, Fluorard FC4430 (manufactured by Sumitomo 3M); FSO, FSO-100, FSN, FSN-100, FS-300 (manufactured by Dupont); FT-250, 251 (manufactured by Neos) and the like.

  As the polyoxyethylene derivative, it is preferable to use an acetylene glycol surfactant. Specific examples include Surfinol 82, 104, 465, 485, TG (all manufactured by Air Products Japan Co., Ltd.), Olphine STG, E1010 (all manufactured by Nissin Chemical Co., Ltd.), Nissan Nonion A-10R, A-. 13R (all manufactured by NOF Corporation), Floren TG-740W, D-90 (manufactured by Kyoeisha Chemical Co., Ltd.), Neugen CX-100 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

  The content of the surfactant in the oil-based recording liquid according to the present embodiment is preferably 0.05% by mass to 3% by mass, more preferably 0.1% by mass to 2% by mass, and still more preferably 0.8%. It is 5 mass% or more and 1 mass% or less.

  Furthermore, the oil-based recording liquid according to the present embodiment has predetermined performance such as a pH adjuster, a chelating agent such as ethylenediaminetetraacetate (EDTA), an antiseptic / antifungal agent, and a rust preventive, as necessary. A substance for imparting can be added.

1.5. Method for Producing Oil-Based Recording Liquid The oil-based recording liquid according to this embodiment can be produced by a known conventional method. First, a pigment, a dispersant, and an oily medium (part) are mixed, and then a pigment dispersion is prepared by a ball mill, a bead mill, an ultrasonic wave, a jet mill or the like, and adjusted to have desired ink characteristics. Subsequently, an oily recording liquid can be obtained by adding an oily medium (remaining amount) and other additives (for example, a surfactant or a binder resin) under stirring.

1.6. Physical Properties The oil-based recording liquid according to the present embodiment preferably has a surface tension at 20 ° C. of 20 mN / m or more and 50 mN / m from the viewpoint of the balance between recording quality and reliability as an ink-jet ink composition. More preferably, it is at least 40 mN / m. The surface tension is measured by using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) by confirming the surface tension when the platinum plate is wet with ink in an environment of 20 ° C. can do.

  From the same viewpoint, the viscosity of the oil-based recording liquid according to the present embodiment at 20 ° C. is preferably 2 mPa · s or more and 30 mPa · s or less, and more preferably 2 mPa · s or more and 20 mPa · s or less. . The viscosity is measured by using a viscoelasticity tester MCR-300 (manufactured by Pysica Corporation), increasing the Shear Rate to 10 to 1000 in an environment of 20 ° C., and reading the viscosity at Shear Rate 200. Can be measured.

2. Inkjet Recording Method Next, the inkjet recording method according to the present embodiment will be described. The ink jet recording method according to the present embodiment performs recording with the above-described oil-based recording liquid.

2.1. Inkjet Recording Apparatus Next, an example of an inkjet recording apparatus in which the inkjet recording method according to this embodiment is performed will be described with reference to the drawings. The ink jet recording apparatus that can be used in the ink jet recording method according to the present embodiment is not limited to the following modes.

  Examples of the ink jet apparatus include an ink jet printer (hereinafter referred to as a printer) equipped with the ink jet head shown in FIG. As shown in FIG. 1, the printer 1 is a device that records an image or the like by ejecting liquid ink onto the surface of a recording medium 2 such as recording paper. The printer 1 includes an inkjet head 3, a carriage 4 to which the inkjet head 3 is attached, a carriage moving mechanism 5 that moves the carriage 4 in the main scanning direction (the longitudinal direction of the printer 1, that is, the width direction of the recording medium 2), and recording. A transport mechanism 6 for transporting the medium 2 in the sub-scanning direction (a direction orthogonal to the main scanning direction) is provided.

  Here, the oil-based recording liquid used in the ink jet recording apparatus is stored in the ink cartridge 7. The ink cartridge 7 is detachably attached to the inkjet head 3. A configuration in which the ink cartridge 7 is disposed on the main body side of the printer 1 and is supplied from the ink cartridge 7 to the inkjet head 3 through an ink supply tube may be employed.

  The carriage moving mechanism 5 includes a timing belt 8. The timing belt 8 is driven by a pulse motor 9 such as a DC motor. Accordingly, when the pulse motor 9 is operated, the carriage 4 is guided by the guide rod 10 installed on the printer 1 and reciprocates in the main scanning direction.

  A platen 11 is arranged below the inkjet head 3 during the recording operation. The platen 11 is disposed to be opposed to a nozzle forming surface (nozzle plate; not shown) of the inkjet head 3 when performing a recording operation, and supports the recording medium 2. Further, a flushing box 12 is provided at an end portion of the platen 11 in the main scanning direction, specifically, an area outside the area (recording area) where ink is ejected to the recording medium 2 disposed on the platen 11. . The flushing box 12 is a member that collects the oil-based recording liquid ejected from the inkjet head 3 when, for example, preliminary discharge of the oil-based recording liquid is performed. The flushing box 12 of the present embodiment is formed in a box shape that opens upward (to the inkjet head 3 side). An ink absorbing material (not shown) made of, for example, urethane sponge is disposed on the bottom surface inside the flushing box 12. The flushing boxes 12 are preferably provided on both sides of the platen 11 in the main scanning direction, but may be provided on at least one side.

  The ink-jet head 3 is means for attaching an oil-based recording liquid to the recording medium 2 and includes a nozzle (not shown) that discharges the oil-based recording liquid. As a method for discharging the oil-based recording liquid from the nozzle, for example, a strong electric field is applied between the nozzle and the acceleration electrode placed in front of the nozzle, and droplet-like oil-based recording liquid is continuously discharged from the nozzle. A method in which droplets of recording liquid are ejected in response to the recording information signal while flying between the deflection electrodes (electrostatic suction method); pressure is applied to the oil-based recording liquid with a small pump, and the nozzle is machined with a quartz vibrator, etc. Forcibly ejecting oil-based recording liquid droplets by oscillating mechanically; pressure and recording information signal are simultaneously applied to the oil-based recording liquid by a piezoelectric element to eject and record oil-based recording liquid droplets ( Piezo method); a method (thermal jet method) in which an oil-based recording liquid is heated and foamed with a microelectrode in accordance with a recording information signal, and droplets of the oil-based recording liquid are discharged and recorded.

  As the ink-jet head 3, either a line-type ink-jet head or a serial-type ink-jet head can be used, but in this embodiment, a serial-type ink-jet head is used.

  Here, the ink jet recording apparatus provided with the serial ink jet head refers to recording by performing a plurality of scans (passes) for discharging the ink composition while moving the recording head relative to the recording medium. Is to do. In a specific example of the serial type recording head, a recording head is mounted on a carriage that moves in the width direction of the recording medium (a direction that intersects the conveyance direction of the recording medium), and the recording head accompanies the movement of the carriage. In which liquid droplets are ejected onto the recording medium by moving.

  On the other hand, an ink jet recording apparatus equipped with a line type ink jet head performs recording by performing a scan (pass) for discharging the ink composition once while moving the recording head relative to the recording medium. It is. A specific example of the line-type recording head is one in which the recording head is formed wider than the width of the recording medium, and droplets are ejected onto the recording medium without moving the recording head.

Although not shown, the ink jet apparatus may be provided with a drying means. By providing the drying means, the liquid medium can be quickly evaporated and scattered from the oil-based recording liquid adhered to the recording medium, and a recorded image or the like can be formed quickly. The drying means that can be employed as the drying means is not particularly limited as long as it has a configuration that promotes evaporation and scattering of the liquid medium contained in the oil-based recording liquid. For example, means for applying heat to the recording medium, means for blowing air on the oil-based recording liquid, means for combining them, and the like can be mentioned. Specifically, forced air heating, radiation heating, conductive heating, high frequency drying, microwave drying, and the like are preferably used.

  Further, the drying by the drying means is preferably drying accompanied by heating, and it is preferable that the ink jet recording apparatus perform recording by discharging to a heated recording medium. The heating method is not particularly limited, and examples thereof include a heat press method, a normal pressure steam method, a high pressure steam method, and a thermofix method. Examples of the heating means for the recording medium include infrared rays (lamps). It is done. In this case, the temperature of the heated recording medium is preferably 30 ° C. or higher and 50 ° C. or lower, and more preferably 30 ° C. or higher and 40 ° C. or lower. In this case, drying of the ink in the recording process can be promoted.

2.2. Recording medium In this embodiment, the recording medium to be printed is not particularly limited, and can be used for any type of recording medium such as plain paper, coated paper, plastic film, fabric, leather, etc., and has low ink absorption. Alternatively, a non-absorbable recording medium may be used.

In the present specification, the “ink-absorbing or non-absorbing recording medium” refers to a recording medium having a property of not absorbing or hardly absorbing an ink composition. Quantitatively, a non-ink-absorbing or low-absorbing recording medium is a “recording medium having a water absorption of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method”. Point to. This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (JAPAN TAPPI). For details of the test method, refer to Standard No. of “JAPAN TAPPI Paper Pulp Test Method 2000”. 51 "Paper and paperboard-Liquid absorbency test method-Bristow method". On the other hand, an ink-absorbing recording medium refers to a recording medium that does not correspond to a non-ink-absorbing or low-absorbing recording medium.

  Examples of non-ink-absorbing recording media include plastic films that do not have an ink absorbing layer, those that are coated with plastic on a substrate such as paper, and those that have a plastic film adhered thereto. . Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

  Examples of the recording medium with low ink absorption include a recording medium provided with a coating layer for receiving ink on the surface. For example, as the base material is paper, art paper, coated paper, mat For example, when the base material is a plastic film, a hydrophilic polymer is applied to the surface of polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc. , Silica and titanium particles are coated with a binder. These recording media may be transparent recording media.

2.3. Recording process (oil-based recording liquid adhesion process)
Next, the recording process will be described. In the present embodiment, the recording step is a step of recording an image by attaching an oil-based recording liquid to the surface of a recording medium. As a result, an image made of an oil-based recording liquid is formed on the surface of the recording medium.

In the present invention, “image” refers to a recording pattern formed from a group of dots, and includes text printing and solid images. Note that a “solid image” means that dots are recorded for all of the pixels that are the minimum recording unit area defined by the recording resolution. Normally, the recording area of the recording medium is covered with ink and the ground of the recording medium is recorded. This means an image pattern that should be an image that cannot be seen.

The maximum adhesion amount of the oil-based recording liquid to the recording medium surface is preferably 5 mg / inch ^{2 to} 15 mg / inch ² . It is preferable that the maximum adhesion amount of the oil-based recording liquid on the surface of the recording medium is within the above range because the recording speed can be increased.

  In addition, you may provide the drying process which dries the oil-based recording liquid adhering to the recording medium after a recording process. In this case, it is preferable to perform drying to such an extent that no stickiness is felt when the oily recording liquid adhered to the surface of the recording medium is touched. The drying step of the oil-based recording liquid may be performed by natural drying, but is preferably drying with heating. The method for heating the oil-based recording liquid is not particularly limited, and examples thereof include the heating method described above.

  In the ink jet recording method used in the present embodiment, by using the oil-based recording liquid according to the present embodiment in which the pigment is stably dispersed, the droplet formability when ejected from the ink jet nozzle is improved. For this reason, the ejection stability is improved, and continuous stable ejection is possible particularly in high-speed line-type ink jet recording. Further, since the pigment is more stably dispersed in the recording liquid, the color developability and fastness of the obtained image are ensured.

3. EXAMPLES Hereinafter, the present invention will be described more specifically with reference to experimental examples and comparative examples, but the present invention is not limited to these examples.

3.1. Sample preparation 3.1.1. Preparation of pigment (Pigment 1)
First Gen Super Magenta RTS (500 g) manufactured by DIC Corporation, 2000 g of crushed salt (salt) and 2000 g of diethylene glycol are mixed, and then subjected to salt milling at 80 ° C. for 6 hours using a 10-liter double arm kneader (TK10) manufactured by Toshin Co., Ltd. A kneaded product containing 1 was obtained. The kneaded product was placed in a 20 L stainless steel stirring vessel, and 15 L of ion exchange water was added and stirred for 1 hour, which was filled in a filter press to squeeze out moisture. This was repeated 5 times, and it was confirmed that the electrical conductivity of the filtrate was below the detection limit. The wet cake thus produced was dried and ground to obtain Pigment 1.

  Pigment 1 Dry powder 1g, dodecylbenzenesulfonic acid Na salt (Neopelex G-85 manufactured by Kao Corporation) 1g, ion-exchanged water 20g are mixed and dispersed with an ultrasonic homogenizer (US-50 manufactured by Nippon Seiki Seisakusho Co., Ltd.). Processing was performed, and 0.05 g of the dispersion was dropped onto plain paper and allowed to air dry. After vapor deposition treatment with Pt on the dried material, the pigment particles on the paper surface are observed with SEM (S-4800 manufactured by Hitachi, Ltd.), and the perimeter of each pigment particle is measured from the observed image. Was calculated as the particle diameter of the pigment particles.

(Pigment 2)
Pigment 2 was produced under the same conditions as for Pigment 1 except that the amount of ground salt (salt) added in the production method of Pigment 1 was changed to 5000 g and the salt milling time was changed to 9 hours.

(Pigment 3)
Pigment 3 was produced under the same conditions as for Pigment 1 except that the salt milling time in the production method of Pigment 1 was changed to 3 hours.

3.1.2. Preparation of resin (Resin 1: Urethane-modified acrylic resin)
A separable flask having a capacity of 5 L was charged with a Dimroth condenser, a stirring blade, and a dropping funnel, and immersed in an oil bath at 60 ° C. for 1 hour while purging with nitrogen. A monomer solution (700 g of dodecyl methacrylate, 150 g of styrene, 100 g of Karenz MOI-BM manufactured by Showa Denko KK, 50 g of Blemmer ANP-300 manufactured by Nippon Oil & Fats Co., Ltd.), 500 g of isooctyl palmitate and a polymerization initiator (Wako Pure Chemical Industries, Ltd.) V-65) manufactured by Kogyo Co., Ltd. 10 g and 10 g of dodecyl mercaptan were added and filled in a dropping funnel, and the mixture was dropped over 2 hours. After dropping, stirring was continued for another hour, 2.0 g of V-65 was added, and stirring was further continued for 1 hour to obtain an acrylic trunk polymer. Thereafter, the temperature of the oil bath was raised to 150 ° C. while refluxing, and stirring was continued for 1 hour to deblock the isocyanate monomer, and the desorbed 1-methylpropylideneamine was distilled off. The temperature of the oil bath was set to 60 ° C., 94 g of dipropylene glycol and 238 g of Takenate 600 manufactured by Mitsui Chemicals, Inc. were mixed, filled in the dropping funnel, and dropped over 1 hour. Thereafter, 854 g of isooctyl palmitate was added and mixed and dissolved to obtain a resin 1 50% by mass solution. Using DMF as a developing solution, the molecular weight of Resin 1 was measured by GPC (HLC-8320GPC manufactured by Tosoh Corporation).

(Resin 2: Fatty acid-modified alkyd resin)
A 20-liter separable flask was charged with a Dimroth condenser and a stirring blade, and heated to 260 ° C. while being purged with nitrogen, and sufficiently purged with nitrogen and heated. 2960 g of phthalic anhydride, 1420 g of linseed oil fatty acid, 990 g of pentaerythritol, and 2100 g of glycerin were added and reacted while stirring. When the acid value became 30 or less, 10 g of paratoluenesulfonic acid was added and the acid value was 20 or less. The reaction was continued until Thereafter, the reaction system was adjusted so that the 33 mass% linseed oil viscosity was 8.0 Pa · S, and the pressure was reduced at 0.02 MPa for 10 minutes. Then, it cooled and the resin 2 was obtained. Further, a part of the resin 2 was dissolved in isooctyl palmitate to obtain a 50 mass% resin 2 solution.

(Resin 3: Urethane-modified alkyd resin)
A separable flask having a capacity of 5 L was charged with a Dimroth condenser, a stirring blade, and a dropping funnel, and immersed in an oil bath at 110 ° C. for 1 hour while purging with nitrogen, and was sufficiently purged with nitrogen and heated. Resin 2 (solid) 612.4g, propylene glycol 4.4g, diethanolamine 6.0g isooctyl palmitate 225.7g was added there, and it stirred and melt | dissolved, purging with nitrogen. Then, after maintaining at 110 ° C. for 2 hours, 0.4 g of dibutyltin dilaurate was added and stirred, and 22.5 g of Takenate 600 and 202.5 g of isooctyl palmitate were added to the solution over 30 minutes from the dropping funnel. Added inside. After dropping, the dropping funnel was washed with 184.2 g of isooctyl palmitate, and the washing liquid was filled in the flask. The temperature was maintained at 110 ° C., the reaction was performed for 6 hours, and the mixture was cooled to obtain a resin 3 solution (50 mass%).

(Resin 4: Acrylic resin)
A separable flask with a capacity of 5 L was charged with a Dimroth condenser, a stirring blade, and a dropping funnel, and immersed in an oil bath at 60 ° C. for 1 hour while purging with nitrogen, and sufficiently purged with nitrogen and heated. A monomer solution (700 g of dodecyl methacrylate, 250 g of styrene, 50 g of Blenmer Blenmer ANP-300 manufactured by Nippon Oil & Fats Co., Ltd.) was prepared, 500 g of isooctyl palmitate, and 10 g of a polymerization initiator (V-65 manufactured by Wako Pure Chemical Industries, Ltd.), 10 g of dodecyl mercaptan was added, filled in the dropping funnel, and dropped over 2 hours. Stirring was continued for an additional hour after the addition, 2.0 g of V-65 was added, and the mixture was further stirred for 1 hour to obtain acrylic resin 4. Thereafter, 500 g of isooctyl palmitate was added and mixed and dissolved to obtain a resin 4 50 mass% solution. GPC (Tosoh Corporation H
LC-8320GPC), the molecular weight of Resin 4 was measured.

3.1.3. Ink Preparation (Example 1)
5000 g of Exol D130, 600 g of pigment 1 and 1000 g of resin 1 solution were placed in a 20 L stainless steel container and stirred for 1 hour with a dissolver manufactured by Inoue Manufacturing Co., Ltd. to prepare a mill base. The mill base was Star Mill LMZ (peripheral speed 12 m / s, beads used: zirconia φ0.1 mm, bead filling rate: 85%) manufactured by Ashizawa Finetech Co., Ltd., and a 5-pass dispersion treatment was performed in a pass operation. Thereafter, the mixture was subjected to a centrifugal treatment at an acceleration of 11,000 G for 20 minutes with a cooling centrifuge (CR7N) manufactured by Hitachi Koki Co., Ltd., and then filtered with a 3 μm filter. The ink of Example 1 was obtained by adding 1000 g of Exol D130, 1000 g of isooctyl palmitate, and 1400 g of hexadecanol to the filtrate and thoroughly stirring.

(Example 2)
The ink of Example 2 was obtained in the same manner except that the resin 1 solution of Example 1 was changed to the resin 2 solution.

(Example 3)
The ink of Example 3 was obtained in the same manner except that the resin 1 solution of Example 1 was changed to the resin 4 solution.

Example 4
4,000 g of Exol D130, 600 g of Pigment 1 and 4000 g of Resin 1 solution were placed in a 20 L stainless steel container and stirred with a dissolver manufactured by Inoue Seisakusho Co., Ltd. for 1 hour to produce a mill base. The mill base was Star Mill LMZ (peripheral speed 12 m / s, beads used: zirconia φ0.1 mm, bead filling rate: 85%) manufactured by Ashizawa Finetech Co., Ltd., and a 5-pass dispersion treatment was performed in a pass operation. Thereafter, the mixture was subjected to a centrifugal treatment at an acceleration of 11,000 G for 20 minutes with a cooling centrifuge (CR7N) manufactured by Hitachi Koki Co., Ltd., and then filtered with a 3 μm filter. The ink of Example 4 was obtained by adding 1400 g of hexadecanol to the filtrate and stirring sufficiently.

(Example 5)
Ink of Example 5 was obtained in the same manner except that the resin 1 solution of Example 4 was changed to the resin 2 solution.

(Example 6)
1000 g of isooctyl palmitate, 600 g of pigment 1 and 4000 g of resin 1 solution were placed in a 20 L stainless steel container and stirred for 1 hour with a dissolver manufactured by Inoue Seisakusho Co., Ltd. to produce a mill base. The mill base was Star Mill LMZ (peripheral speed 12 m / s, beads used: zirconia φ0.1 mm, bead filling rate: 85%) manufactured by Ashizawa Finetech Co., Ltd., and a 5-pass dispersion treatment was performed in a pass operation. Thereafter, the mixture was subjected to a centrifugal treatment at an acceleration of 11,000 G for 20 minutes with a cooling centrifuge (CR7N) manufactured by Hitachi Koki Co., Ltd., and then filtered with a 3 μm filter. To the filtrate, 3000 g of isooctyl palmitate and 1400 g of hexadecanol were added and stirred sufficiently to obtain the ink of Example 6.

(Example 7)
2000 g of Exol D130, 600 g of pigment 1 and 1000 g of resin 1 solution were placed in a 20 L stainless steel container and stirred for 1 hour with a dissolver manufactured by Inoue Manufacturing Co., Ltd. to produce a mill base. Star Mill LMZ made by Ashizawa Finetech Co., Ltd.
(Passing speed: 12 m / s, beads used: zirconia φ0.1 mm, beads filling rate: 85%), a 5-pass dispersion treatment was performed by a pass operation. Then, it centrifuged for 20 minutes by the acceleration 11,000G with the Hitachi Koki cooling centrifuge (CR7N), and filtered with the 3 micrometer filter after that. The ink of Example 7 was obtained by adding 3000 g of isooctyl palmitate and 3400 g of hexadecanol to the filtrate and stirring sufficiently.

(Example 8)
The ink of Example 8 was obtained in the same manner except that the resin 1 solution of Example 1 was changed to the resin 4 solution.

(Comparative Example 1)
Ink of Comparative Example 1 was obtained in the same manner except that Pigment 1 of Example 1 was changed to Pigment 2.

(Comparative Example 2)
Ink of Comparative Example 2 was obtained in the same manner except that Pigment 1 of Example 1 was changed to Pigment 3.

3.2. Evaluation test 3.2.1. Sedimentation stability test A centrifuge tube of Hitachi Koki Co., Ltd. cooled centrifuge (CR7N) was filled with 1000 ml of the evaluation ink, and centrifuged at 7,000 rpm (11,100 G) for 1 hour. After the treatment, 10 ml of the supernatant was collected and the absorbance was measured and evaluated according to the following criteria.
(Evaluation criteria)
○: The amount of decrease in the absorbance at the peak wavelength from the initial stage is less than 5% ×: The amount of decrease in the absorbance at the peak wavelength from the initial stage is 5% or more

3.2.2. Clogging recovery test An ink jet printer PX-7050 remodeled machine manufactured by Seiko Epson Corporation was filled with the above inks, and 1000 sheets of A4 paper were continuously printed. Thereafter, the head was removed and 40 ° C./30% R.D. H. After leaving it in the environment, it was mounted on the printer again, and printing was performed to check for clogging. If there was no clogging, the above-mentioned standing was repeated again until the discharge failure due to clogging occurred. After clogging occurred, head cleaning was performed, and a nozzle check pattern was printed again to confirm recovery, and evaluation was performed according to the following criteria.
(Evaluation criteria)
○: Clogging is eliminated within 3 head cleanings ×: Clogging is not eliminated within 3 head cleanings

3.2.3. Color development test Each ink was filled in an ink jet printer PX-7050 remodeled machine manufactured by Seiko Epson Corporation, solid printing was performed on plain paper (P paper A4 manufactured by Fuji Xerox Co., Ltd.), and the following criteria were evaluated.
(Evaluation criteria)
○: OD is 1.2 or more ×: OD is less than 1.2

3.2.4. Light Resistance Test Based on JEITA (Electronic Information Technology Industries Association) standard CP-3901A, evaluation was performed according to the following criteria.
(Evaluation criteria)
○: Indoor light-resistant life prediction year of OD1.0 patch is 45 years or more ×: Indoor light-proof life prediction year of OD1.0 patch is less than 45 years

3.2.5. Ejection stability test Inkjet printer manufactured by Seiko Epson Corporation PX-7050 remodeled machine is filled with the above inks, and 2P character quality, 1 dot ruled line (vertical, horizontal) on plain paper (P paper A4 manufactured by Fuji Xerox Co., Ltd.) The test pattern including the ink was continuously printed on 1000 sheets and evaluated according to the following criteria.
(Evaluation criteria)
5: Defect rate less than 0.1% 4: Defect rate 0.1% or more and less than 1% 3: Defect rate 1% or more and less than 5% 2: Defect rate 5% or more and less than 10% 1: Defect rate 10% or more

顔料の一次粒子径が本発明の範囲から外れる比較例１、２では、吐出安定性と他の性能
を両立させることができなかった。これに対し、実施例では、顔料の一次粒子径が本発明の範囲であることにより、多くの評価を満たすことができた。特に、樹脂として、ウレタン変性アクリル樹脂、脂肪酸変性アルキド樹脂及びウレタン変性アルキド樹脂のいずれかを使用した場合には、吐出安定性と他の性能との両立が可能であった。また、ナフテン系溶剤の含有量が高い方が、性能が向上する傾向にあった。 3.3. Evaluation results The above evaluation results are shown in Table 1.

In Comparative Examples 1 and 2 in which the primary particle diameter of the pigment deviates from the scope of the present invention, it was impossible to achieve both ejection stability and other performances. On the other hand, in the Examples, many evaluations could be satisfied because the primary particle diameter of the pigment was within the range of the present invention. In particular, when one of a urethane-modified acrylic resin, a fatty acid-modified alkyd resin, and a urethane-modified alkyd resin is used as the resin, it is possible to achieve both discharge stability and other performances. Further, the higher the naphthenic solvent content, the better the performance.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording medium, 3 ... Inkjet head, 4 ... Carriage, 5 ... Carriage moving mechanism, 6 ... Conveyance mechanism, 7 ... Ink cartridge, 8 ... Timing belt, 9 ... Pulse motor, 10 ... Guide rod, 11 ... Platen, 12 ... Flushing box

Claims (6)

Containing a pigment, an oily medium, and a resin;
An oil-based recording liquid for inkjet, wherein a 10% integrated value (D10) of a number distribution of primary particle diameters of the pigment is from 40 nm to 80 nm and a 90% integrated value (D90) is from 90 nm to 150 nm.   The oil-based recording liquid for inkjet according to claim 1, wherein the resin is at least one selected from the group consisting of a urethane-modified acrylic resin, a fatty acid-modified alkyd resin, and a urethane-modified alkyd resin. The oily medium contains a petroleum solvent, a fatty acid ester and a higher alcohol;
The oil-based recording liquid for ink jet according to claim 1 or 2, wherein the petroleum solvent is a naphthenic solvent.   The oil-based recording liquid for inkjet according to any one of claims 1 to 3, wherein the content of the resin dissolved in the oil-based medium is 0.1% by mass or more and 2% by mass or less.   The mass ratio of the pigment and the dispersant (pigment / dispersant) in the oil-based recording liquid for inkjet is in the range of 0.5 or more and 2.0 or less. 2. An oil-based recording liquid for ink jet recording according to item 1.   An ink jet recording method in which recording is performed with the oil-based recording liquid for ink jet according to any one of claims 1 to 5.

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